The transmission mount in your car is what secures your transmission to the chassis of your car. Without your transmission mount in place, there's nothing holding your transmission at all. Just like your motor has a mount that holds it in place, so too does the transmission mount secure it along transmission mount brackets in an effort to both keep it right where it belongs in your vehicle and also ensure that all the linkages and driveshaft are in the correct position while limiting vibration and shaking as much as possible. If your transmission mount has a problem and you need to get it replaced, then a mechanic will likely charge you somewhere between $200 in $500 to get it fixed.
It's a bit of a range to predict the cost of this particular replacement simply because it heavily depends on the make, model, and year of your vehicle as well as the mechanic you're taking it too. The transmission mount is a difficult piece of your vehicle’s assembly to get to which is why it cost a little extra in labour then some other repairs might. Unfortunately, if your transmission mount has failed you absolutely need to get it fixed as soon as possible to ensure the safe and correct operation of your vehicle.
What is a Transmission Mount?
As we said, a transmission mount secures the transmission in your vehicle. That's what it does, but what exactly is it? You can head to AutoZone and take a look at what a transmission mount looks like if you haven't seen one before, and also get an idea for the prices. New transmission mounts will typically cost you between $20 and $100. Essentially a transmission mount is a rubber or urethane shock absorber, a kind of bushing that is bolted or otherwise secured to a bracket. That whole part together is then secured to the vehicle and there are often a pair of these mounts, but sometimes even more secure in your transmission in place.
How Long Do Transmission Mounts Last?
Because transmission mounts undergo a fair amount of wear and tear during their lifetime you can expect them to last you about 60,000 miles to 100,000 miles and potentially much longer. The rubber or urethane they are made from is susceptible to oxidation overtime and the excessive heat and vibrations can wear down the steel brackets that they are connected to as well. Aside from that, accident damage as well as work done on the engine or transmission that requires the removal of the assembly can also end up causing damage that will shorten the lifespan of your transmission mounts as well.
What are the Symptoms of a Bad Transmission Mount?
If your transmission mounts are failing there are some signs you can be on the lookout for to let you know that there is a problem. It's possible that something like an accident could damage them as well. If you've been hit by another car, the outside damage may not be noticeable, but it's possible if it hit the transmission mount inside then you could be looking at some of these problems. Likewise, if you drive a manual transmission vehicle and have a tendency to over rev the engine or otherwise push your vehicle hard, you might also experience some of these symptoms.
When your transmission mounts are failing you may notice some distinctive loud sounds to alert you to the problem. There should be banging, bashing, and thumping sounds coming from under your hood. It may bring to mind the idea that perhaps your entire engine is on the verge of falling out of the car. These are the sounds of metal banging against metal as the parts shift around because the mounts are no longer able to secure them. Despite the aggressive sound, it's very unlikely that the entire transmission is going to fall out of the car, but it also doesn't mean you should be driving around in this condition either. Because the transmission is loose, the whole system will be shaking and banging other parts and it will only get worse the longer it's allowed to continue.
A thumping sound is more likely to occur as you drive over uneven ground. If you hit potholes, speed bumps, or other bumps in the road this will make the transmission shift and thump as it rises and falls in position, much the way you feel yourself bounce in your seat when you hit these uneven spots in the road.
As we've said that the transmission mounts are part shock absorber which means their job is to absorb vibrations. When they're not working the way they should, the vibration in your engine will increase significantly to the point where you are going to be feeling it excessively in the cabin of your vehicle as well.
When you first start your vehicle if you are experiencing a rocking motion, or your vehicle is sort of lurching forward and backwards even though you haven't gone anywhere yet that's a good sign that your transmission mount has failed. This is very common in front wheel drive vehicles. If you have a rear wheel drive vehicle and your transmission mount has gone bad, then the rocking motion will occur in a side-to-side motion. It will even out into just a study vibration over time, but when you first start the vehicle up, you'll have a distinct back and forth rocking motion.
When you turn the vehicle off, at the moment the ignition goes off you'll also notice a kind of lurching or surging motion from the car every time as well.
When your transmission mount is not holding things securely, you'll notice this especially as you turn corners. Everything will shift with the motion of the vehicle in balancing the weight overall. Think of what it's like when you're on a roller coaster and you take a hard turn, and the momentum forces you to the opposite side of the seat. That's what happens in the engine of your vehicle when the mounts aren’t securing the transmission or the engine properly anymore.
This can be more than just a distraction and can potentially cause some precarious and dangerous situations if you turn too quickly and the inertia is too great that it causes difficulty in maintaining control of your vehicle as you turn.
When your transmission mount has failed, it can create a cascade effect that moves on to nearby parts. In particular transmission linkages, the wires, and hoses that are located around the transmission in your vehicle will be some of the first to show signs of stress and damage if the mounts are failing and your transmission is unsecured. You could do a visual inspection and see if there's any evidence that these are being damaged as a result.
This is one of the more extreme side effects of a problem with your transmission mounts not working properly. As you go over bumps and uneven ground, as you continue to corner and make sharp turns, the movement of the transmission is no longer secure and can actually cause the frame of your vehicle to flex and bend. Eventually it can get bent completely out of shape. This can cause severe problems with other parts of your engine no longer being correctly aligned, and even prevent your doors from closing and locking correctly.
This is one of the most extreme side effects of a problem with your transmission mounts and if this happens you will likely have noticed the other symptoms we mentioned already ahead of time. However, if you let them go on and off without getting it fixed, this could be one of the end results.
Can You Drive with a Bad Transmission Mount?
As you can see if you have a bad transmission mount in your vehicle then you're going to have a number of potential signs to indicate that something has gone wrong. None of the things we have listed specifically indicate that your vehicle will no longer be able to drive at all. In fact, you could drive for quite a while with a bad transmission mount. The last side effect that we mentioned, the one relating to frame and chassis bending, is the result of driving for an extended period of time with an unreliable transmission mount.
So, the answer to the question can you drive with a bad transmission mount is both yes and no. Yes, in the literal sense that you can definitely keep driving for a while, but no in the sense that you should not be driving with a bad transmission mount. All of the symptoms we listed will get worse over time and can lead to more extensive damage down the road if the problem doesn't get repaired.
In time a bad transmission mount can cause some serious damage to your transmission alignment including the link between the transmission and the driveshaft. That can make it literally impossible to drive at some point in time so, if you do let this go long enough, then you will not be able to drive with a bad motor mount.
Additionally, if the damage to your transmission mount is bad enough then the transmission housing itself can crack or break and you could end up having a completely destroyed transmission if the damage becomes bad enough.
The cost of replacing the transmission in your vehicle could be quite high if the damage is bad enough. Rebuilding a transmission could cost you between $2,500 and $4,000. If rebuilding is not an option and you need the entire transmission replaced, that can cost you between $3,000 and $6,000. The prices really are all over the map and depend heavily on not just where you are getting the repairs done, but the make, model, and year of your vehicle as well. Suffice it to say that no matter what kind of car you have, if you need the transmission fixed it's going to be a remarkably expensive repair.
Compare the price of repairing a transmission with the price of just getting the transmission mounts replaced when they go bad and you'll see that it's definitely not the kind of repair job you want to let slide. If you experience any of the symptoms that your transmission mounts are failing, get it repaired as soon as you can so you don't have to deal with these much bigger, costly or repair jobs down the road.
The Bottom Line
Transmission mounts are fairly simple parts of your vehicle that most drivers either don't give a lot of thought to or aren't even aware that they exist. When they're doing their job properly, we have no reason to think about them and that's precisely the way you want it to be. However, when they start to fail you will get some of the most dramatic side effects you'll ever experience in your vehicle as a result.
Even though you can push the limits of how long you can drive a vehicle without having the transmission mounts functioning properly, you really don't want to let this one slide for too long. As we've said the cost of repairing or replacing a transmission can be quite high and also the risk of further damage and even potential accidents because of the effect of your transmission shifting around so much in your vehicle can be serious.
At $200 to $500, a transmission mount replacement isn't a cheap repair job by any means but when compared to the damage that could occur if you don't get it done, it's merely a drop in the bucket and the kind of job that you don't want to put off any longer than you should. If you notice any of the symptoms, we've mentioned of a bad transmission mount then you should be getting into a qualified mechanic as soon as you can to get the problem diagnosed and fixed as soon as possible.